Recent Publications
The intention of publications made by Atotech is to share the results of our extensive research and development on a non commercial basis. With these presentations we aim to provide in-depth process information and inform about the latest investigations and results in each technology field. It should enable the reader to gain a complete and comprehensive understanding of our process solution and of general phenomena encountered in the electroplating industry.
This segment presents the recent papers from the business technology team desmear and metallization.
- This graphic shows the temperature profiles for lead free soldering versus traditional lead containing solder. (click in picture for close up view)
Influence of Electroless Copper on IC Reliability
Tafadzwa Magaya, Atotech Deutschland GmbH, October 2008
The process of plating through holes (PTH) is inherent to modern PCB manufacturing. In an arena of increasing circuit density and layer counts, the reliability of the PTH process is under constant microscopic examination. The aim of electroless copper is to plate a conductive layer through a hole or into a blind microvia. In this context an interconnect (IC) refers to the copper to copper adhesion within the functional constraints of a circuit board. As these can include many inner layers, the inter connection quality is of prime concern. In addition the PTH process also inherits the issues from the preceding manufacture.
Download complete paper here: pdf file (File size 270 kB)
- Blister Free Deposition on Polyimide with Printoganth P Process (click in picture for close up view)
Blister Free PTH Processes for High Tg and Exotic Base Materials
Tafadzwa Magaya, Atotech Deutschland GmbH, May 2007
PCB manufacturers must permanently contend with difficulties associated with production of PCBs with ever more complex designs, technology requirements and increased lifetime / reliability requirements. Issues pertaining to the laminate material used, via sizes, copper layer thickness and electrical requirements, which significantly affect the manufacturing process are often the prerogative of PCB designers with extremely limited if at all any consultation of manufacturers.
Download complete paper here: pdf file (File size 80 kB)
Implementing SPC for Wet Processes
Yvonne Welz, Atotech Deutschland GmbH, February 2002
The PCB industry has a large variety of processes. For the mechanical processes (e.g., drilling, pressing) the use of statistical methods for monitoring and qualifying these processes is standard. Wet chemical processes are more complex, however, and SPC is limited to isolated cases. Yet many process steps are involved, and the potential fault-inducing parameters just as varied.
Customer requirements demand many fabricators apply SPC for all processes. One reason: Many companies base their quality management system on DIN ISO 9000, which requires the use of statistical procedures like subgroup systems, quality control charting, capability studies, and so on.
Download complete paper here: pdf file (File size 200 kB)
- BMV processed with Neopact after Acid copper process
Green Benefits of Improved Direct Plating Processes
Tafadzwa Magaya, Atotech Deutschland GmbH, December 2008
In recent years there has been an increase in environmental awareness globally, which has also influenced the PCB manufacturing industry. New "green" legislation such as WEEE, RoHS and REACH has been introduced to compel PCB manufacturers to employ less harmful manufacturing chemistries.
China for example, has enacted strict standards for new PCB shops especially with regards to wastewater generation, making it harder for manufacturers to acquire production licenses. For the metallization process this has rekindled interest in direct plating (DP) processes, which although often regarded as being technically inferior, are deemed more environmentally friendly than electroless copper. Direct plating can generally be subdivided into two main categories i.e. Pd-based and Conductive Polymer based types.
Both are formaldehyde and cyanide free and the conductive polymer based processes are usually shorter than electroless copper with all associated environmental benefits. This paper will use the example of Atotech's new Seleo CP Plus (conductive polymer) and Neopact (Pd-based) processes to illustrate the environmental benefits of direct plating as well as its technical limitations. Calculations will show relative chemistry and energy consumptions as well as wastewater generation in comparison to electroless copper.
Download complete paper here: pdf file (File size 175 kB)
Pre-treatment and PTH Solutions for Flex-rigid PCBs
Tafadzwa Magaya, Atotech Deutschland GmbH, October 2006
The demand for flex and flex-rigid boards of ever increasing complexity but at lower costs has never been as high as at present. To be able to compete in such a market requires reliable processes with the capability to handle diverse and emerging materials and designs.
This paper will highlight some of the difficulties faced by flex and flex-rigid PCB manufacturers today and will provide working solutions and innovations. Desmear is a common request for flex-rigid materials to ensure good interconnection quality as well as to reduce the comparatively higher costs of plasma processing. The difficulties commonly found with desmearing different lay-ups of flex-rigid will be discussed as well as some useful tips. Pre-treatment is one of the key process steps for ensuring good flex material coverage and adhesion. Several electroless copper pre-treatment concepts as well as a direct concept will be discussed showing the benefits and results for even the most demanding of board layouts and materials.
Download complete paper here: pdf file (File size 250 kB)
Printoganth FF - The Formaldehyde Free Electroless Copper Process
Tom Thieme, Atotech Deutschland GmbH, February 2002
The most commonly known and used metallization technique in PCB manufacturing – electroless copper – will have to meet modern ecological requirements. The main concern is the use of toxic formaldehyde as reducing agent. The Printoganth FF process uses the much more friendly alternative hypophosphite for the reduction of copper ions.
Even though many theoretical and applied investigations have already been published, the final realization for a process that is suitable for continuous mass production has turned out to be difficult. Besides finding the optimum process conditions, the determination of the metallization mechanism is most critical. One of the key factors for a suitable process is the control of deposition speed and deposit structure, which requires the correct formulation of the stabilising system.
Download complete paper here: pdf file (File size 215 kB)
Benefits of Horizontal Desmear and Electroless Copper for High Technology PCB Manufacturing
Neil Patton, Atotech Deutschland GmbH, June 2006
Higher Technical Demands for PCBs means new processing challenges and to achieve reliable and consistent results requires improvements in current techniques. With this paper we will show the benefits of horizontal desmear and electroless copper processing for high technology applications including the latest results from development work.
Download complete paper here: pdf file (File size 180 kB)
Assessment and Solutions for Hole Wall Pull Away in High Tg and High Technology Laminate Materials
Neil Patton, Atotech Deutschland GmbH, March 2004
This paper is split into two main parts; desmear characterisation and assessment of commonly used high technology laminate materials, and improvements that can be made with the electroless copper process to improve hole wall adhesion and reduce blistering.
The desmear part will show the effect of swelling and etching these laminates with different commonly used solvents as well as weight loss results and an assessment of roughness.
The electroless part will show the influence of the electroless copper properties and the adhesion benefits that can be achieved by optimising formulations.
Download complete paper here: pdf file (File size 515 kB)
Flexible PCB Plating Through Hole Considerations, Experiences and Solutions
Neil Patton, Atotech Deutschland GmbH, February 2005
Due to the worldwide increase in demand for flex and flex-rigid panels as well as the shift in the required designs of panels there is an extreme need for improved PTH processing. There are several proven routes for high technology flex / flex-rigid manufacturing as well as for high volume applications, but lately there have been some developments.
From this presentation, along with suitable examples, we aim to give an insight into the current status of flex / flex-rigid manufacturing, from the point of view of PTH processing, as well as suitable solutions to common manufacturing issues.
Download complete paper here: pdf file (File size 290 kB)
Desmear and Plating Through Hole Considerations and Experiences for Green PCB Production
Gerd Linka, Neil Patton, Atotech Deutschland GmbH, March 2006
With the latest legislations from RoHS and WEEE dominating the horizon of the PCB landscape there is a need for manufacturers and their suppliers to understand their impacts. The requirement to remove lead from the industry and therefore the need for lead-free soldering operations means a large amount of stress is placed on the PCB substrates. The laminate material suppliers are responding to the new legislation by introducing newer varieties of materials that have better heat stress handling capacities as well as some added benefits like reduced z-expansion. Another concern for the laminate manufacturers is the need to remove halogen based, flame retardants like bromine from their resin systems.
This paper will discuss the relevant legislations and the impact of these on the desmear and plating through hole processes. We will introduce and discuss the changes that are taking place in the laminate materials sector needed to meet the newer requirements. We will discuss the most significant advances in the halogen free as well as Pb-free capable materials. The significance of the changes and their influence on the desmear and PTH processes will be highlighted. Test results from investigations and experiences with the newer materials will be presented and compared to results normally found for the more standard materials. We will propose options for handling the various issues arising from these new materials and so help to prepare PCB manufacturers for the coming turbulence in the industry being generated by the new legislative demands.
Download complete paper here: pdf file (File size 290 kB)
SELEO CP – New Conductive Polymer Direct Metallization
Tom Thieme, Atotech Deutschland GmbH; May 2003
Due to reduced investment and running costs, their environmental friendliness and the low space requirements, direct metallization (DM) processes have become very popular in the 1990s. The DM sequences itself can be divided into three subgroups, the conductive polymer based, the Carbon based and the Pd colloid based DM processes. While the latter two at some stage require an etch cleaning step, the conductive polymer (CP) sequences are highly selective by nature. With microvia plating and the global penetration of HDI mass production new limitations for some DM processes have been encountered. The CP versions however proved to give excellent, persistent and high yield results.
Download complete paper here: pdf file (File size 490 kB)
The Potential Benefits of a Chemical "Kick Start" for the Autocatalytic Electroless Copper Plating Process
Edith Günther, Atotech Deutschland GmbH, April 2009
The aim of this study is to reduce the disadvantageous and injurious qualities of the autocatalytic reducing agents without affecting the quality of the copper deposits. This can be achieved with a low reducing agent concentration in the copper solution. To compensate for the resulting lack of reducing agent, and thus the lack of essential electrons for the copper deposition, additives are introduced. These additives support the startup process on palladium activated base material during the copper deposition.
This investigation demonstrates that additives can provide a significant benefit in terms of cost, health and environmental impact when compared to the traditional electroless copper process. In that way, a higher concentration of the mostly injurious and cost-intensive reducing agent can be avoided.
Download complete paper here: pdf file (File size 220 kB)